http://hdl.handle.net/11089/56720 2026-04-06T22:51:38Z http://hdl.handle.net/11089/56722 Comparing Sense and Denotation in Bilateralist Proof Systems for Proofs and Refutations Ayhan, Sara In this paper a framework to distinguish in a Fregean manner between sense and denotation of \(\lambda\)-term-annotated derivations will be applied to a bilateralist sequent calculus displaying two derivability relations, one for proving and one for refuting. Therefore, a two-sorted typed \(\lambda\)-calculus will be used to annotate this calculus and a Dualization Theorem will be given, stating that for any derivable sequent expressing a proof, there is also a derivable sequent expressing a refutation and vice versa. By having joint \(\lambda\)-term annotations for proof systems in natural deduction and sequent calculus style, a comparison with respect to sense and denotation between derivations in those systems will be feasible, since the annotations elucidate the structural correspondences of the respective derivations. Thus, we will have a basis for determining in which cases, firstly, derivations expressing a proof vs. derivations expressing a refutation and, secondly, derivations in natural deduction vs. in sequent calculus can be identified and on which level. 2025-05-30T00:00:00Z http://hdl.handle.net/11089/56723 Internal and External Calculi: Ordering the Jungle without Being Lost in Translations Lyon, Tim S.; Ciabattoni, Agata; Galmiche, Didier; Girlando, Marianna; Larchey-Wendling, Dominique; Méry, Daniel; Olivetti, Nicola; Ramanayake, Revantha This paper gives a broad account of the various sequent-based proof formalisms in the proof-theoretic literature. We consider formalisms for various modal and tense logics, intuitionistic logic, conditional logics, and bunched logics. After providing an overview of the logics and proof formalisms under consideration, we show how these sequent-based formalisms can be placed in a hierarchy in terms of the underlying data structure of the sequents. We then discuss how this hierarchy can be traversed using translations. Translating proofs up this hierarchy is found to be relatively straightforward while translating proofs down the hierarchy is substantially more difficult. Finally, we inspect the prevalent distinction in structural proof theory between ‘internal calculi’ and ‘external calculi.’ We discuss the ambiguities involved in the informal definitions of these categories, and we critically assess the properties that (calculi from) these classes are purported to possess. 2025-06-06T00:00:00Z http://hdl.handle.net/11089/56721 Supposition: No Problem for Bilateralism Simonelli, Ryan In a recent paper, Nils Kürbis argues that bilateral natural deduction systems in which assertions and denials figure as hypothetical assumptions are unintelligible. In this paper, I respond to this claim on two counts. First, I argue that, if we think of bilateralism as a tool for articulating discursive norms, then supposition of assertions and denials in the context of bilateral natural deduction systems is perfectly intelligible. Second, I show that, by transposing such systems into sequent notation, one can make perfect sense of them without talking about supposition at all, just talking in terms of relations of committive consequence. I conclude by providing some motivation for adopting this normative interpretation of bilateralism on which this response to Kürbis’s argument is based. 2025-01-08T00:00:00Z